Brace adhesive is a superbly engineered material, designed to give the strongest possible bond with the enamel while also allowing that bond to be broken without harming the tooth when the time comes to remove the braces. There is no such thing as weak brace adhesive – the reason a bracket can come off from hard food is that we do, after all, want to take the braces off all the teeth one day. Unfortunately, the solution to brackets coming off isn't a stronger adhesive, but limiting the foods that can put excessive pressure on the braces.
This answer is for general information. Your own case needs an examination by an orthodontist.